JP10-145205A discloses a switch circuit that interrupts a current supplied to a load when a temperature detected by temperature detecting means reaches or exceeds a predetermined temperature. In this switch circuit, control means open a switch on the basis of a signal from the temperature detecting means, thereby interrupting input of a control signal into a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), and as a result, the current supplied to the load is interrupted.